Danny Boyle's 127 Hours closed the 54th BFI London film festival, just as his Slumdog Millionaire ended the 52nd edition, both years saving one of the best till last. Although 127 Hours is ostensibly a flipside movie to Slumdog, it is in so many ways a typical Boyle movie, the work of a smart and popular artist whose quest for film ecstasy continues unabated.

The story is based on the true one – indeed, one of several at this LFF – of extreme sports enthusiast Aron Ralston, who bounded on stage before the gala to wave to the audience with his one remaining hand. 127 Hours is the story of the other hand, now a hook.

Boyle begins the film at frantic pace over Free Blood's dance anthem "Never Hear Surf Music Again", a song which urges you to "Take It", whatever it is. This opening sequence, with James Franco as Ralston preparing his stuff for a weekend of outdoor thrill-seeking, establishes the film's themes of crowds and individuals, of being part of life's pack or being on your own. These issues come to preoccupy Ralston's brain when he goes off canyoning alone in Utah and gets his arm trapped under a rock for the 127 hours of the title.

It's a physical film that elicits groans, eeks and lurches from its audience. Through its burrowing camerwork, its split screens, its edits, its sound design and soundtrack, its colours and synaesthetic effects and, of course, through its admirable central performance, the film uses all the tricks of modern cinema to stick us right in Ralston's head and body.

The real triumph is that in its clammiest, toughest moments, a hallucinatory passage allows the viewer to trip off on his or her own thoughts. Would we do the same, and if we did, what would be the motivating moment – the thought of an ex-lover, a child, a parent – that persuades us to snap the bone and sever the final tendon? Boyle's filmic alchemy turns agony to rapture and it's certainly a sweaty experience.

You'll have to supply your own puns about arms, hands and cuts. Before showing his film, Danny Boyle made a joke about having failed to close the festival because it seemed to be still here, but he did touch a nerve (OK, a little pun).

While the festival announced record figures, it will obviously continue amid the government funding slashes, but the need for private sponsorship is ever clearer, so maybe a few of the strands need refreshing and refocusing?

I'd like to see more momentum throughout the festival towards the climax of the awards. In the ceremony's second year, a deserved double of best British newcomer and the long-standing Sutherland Award went to Clio Barnard's The Arbor, a genuinely original and brilliant piece of work. The real surprise was that best film went to Russia's How I Ended This Summer by Alexei Popogrebsky. It's certainly a fine film, about two very different men – gruff old-timer Sergei (Sergei Puskepalis) and young student Pavel (Grigoriy Dobrygin) – who crew a meteorological station on an Arctic island. In this clash of generations and ideologies, there's black Russian humour and outstanding photography but I get the feeling a higher-profile, less "arthousey" winner would have secretly pleased the head honchos.

Darren Aronofsky's Black Swan, for example, would have made better headlines, but you can never second guess a jury and the Russian film's victory signals that London is, then, still the place for classy world cinema.

I wrote about British film last week; this LFF also indicated that American cinema is showing signs of recapturing its cool. Terrific films such as Blue Valentine, The Kids Are All Right and Black Swan had a stylistic confidence and indie edge but also audience appeal.

Increasingly, however, the best, freshest work is in the area of documentaries, or more accurately, where documentary techniques tell stories, true or otherwise. British doc Fire in Babylon, by Stevan Riley, was a superb account of the rise of Clive Lloyd and Viv Richards's West Indies cricket team, told thrillingly, with verve, music, pride and eloquence.

Catfish, from America, was a subtle, smart film about Facebook and, for me, far more perceptive about the computer age than The Social Network. It tells of a young New York photographer's relationship with a family that begins on the website and then spills into reality, bringing with it fear, shock and sadness. It really is a quite unusual and unsettling film. The screening for this unknown, no-budget, no-big-names doc, which I attended on a wet Monday afternoon, was packed and buzzing, suggesting that with crowds and appetite like this, the LFF will run and run, no matter how many times Danny Boyle brings it to a close.